The present invention relates to a multipolar step motor. In known motors of this type, cooperation between polar members of a stationary magnetic circuit in the airgap of which the rotor is disposed, and poles of the rotor of the motor, results in a torque acting on the rotor having a component C.sub.1 due to the current and a residual magneto-static torque C.sub.0 defining in particular the positions of stable equilibrium of the rotor. The magneto-static torque C.sub.0 generally comprises a harmonic C.sub.02 having a frequency double than that of the torque due to the current, and a harmonic C.sub.04 having a frequency quadruple than that of the torque due to the current, whereas the odd harmonics are generally negligible. Methods of reducing or controlling the influence of the harmonic 2 of the residual magneto-static torque are already known. However, the more this harmonic 2 is reduced in the magneto-static torque the more the influence of the harmonic 4 becomes conspicuous and troublesome for the operation of the motor. As will be described below, a high percentage of harmonic 4 with respect to the basic harmonic generally has the effect of bringing the stable equilibrium position of the rotor near to the point where the torque due to the current is nul. Consequently, the torque due to the current available in the rest positions is reduced, this resulting in a corresponding reduction of the useful torque of the motor.